CVE-2017-18122
SimpleSAMLphp Signature validation bypass
CVE-2017-18122 is a high vulnerability (CVSS 8.1) in Simplesamlphp, published February 2, 2018. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.09%, the 65th percentile. Fixed in simplesamlphp/simplesamlphp 1.14.17.
A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
8.1
A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.
- Record
CVE-2017-18122- CVSS 3.0
- 8.1 High
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 6.8 Medium
AV:N/AC:M/Au:N/C:P/I:P/A:P - Weakness
- CWE-347
- Updated
- 2026-11-02
CVE List No score
A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.
- Record
CVE-2017-18122- Updated
- 2026-11-02
EUVDEUVD-2022-4278 No score
A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.
- Record
EUVD-2022-4278- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-j4qf-3w33-8cgc
8.1
SimpleSAMLphp Signature validation bypass
A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.
- Record
GHSA-j4qf-3w33-8cgc- CVSS 3.0
- 8.1 High
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-347
- Updated
- 2026-11-02
OSV
8.1
A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.
- Record
CVE-2017-18122- CVSS 3.0
- 8.1 High
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVDEBIAN-CVE-2017-18122
8.1
A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.
- Record
DEBIAN-CVE-2017-18122- CVSS 3.0
- 8.1 High
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVGHSA-j4qf-3w33-8cgc
8.1
SimpleSAMLphp Signature validation bypass
A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.
- Record
GHSA-j4qf-3w33-8cgc- CVSS 3.0
- 8.1 High
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-347
- Updated
- 2026-11-02
OSVUBUNTU-CVE-2017-18122
8.1
A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.
- Record
UBUNTU-CVE-2017-18122- CVSS 3.0
- 8.1 High
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
simplesamlphp/simplesamlphpPackagist |
before 1.14.17 | 1.14.17 |
simplesamlphpDebian:12 |
before 1.15.0-1 | 1.15.0-1 |
simplesamlphpDebian:14 |
before 1.15.0-1, plus listed versions 1.10.0-11.11.0-11.12.0-11.12.0~rc1-11.12.0~rc2-1 Show 34 moreShow less1.13.0-11.13.1-11.13.1-21.13.2-11.14.0-11.14.1-11.14.10-11.14.11-11.14.15-11.14.2-11.14.2-21.14.3-11.14.4-11.14.5-11.14.6-11.14.7-11.14.8-11.14.9-11.6.0-11.6.1-11.6.2-11.6.3-11.6.3-21.6.3-31.7.0-11.7.0-21.8.0-11.8.1-11.8.2-11.9.0-11.9.0~rc1-11.9.0~rc2-11.9.1-11.9.2-1 |
1.15.0-1 |
simplesamlphpDebian:7 |
before 1.9.2-1+deb7u2, plus listed versions 1.9.2-11.9.2-1+deb7u1 |
1.9.2-1+deb7u2 |
simplesamlphpDebian:8 |
before 1.13.1-2+deb8u1, plus listed versions 1.13.1-2 |
1.13.1-2+deb8u1 |
simplesamlphpDebian:9 |
before 1.14.11-1+deb9u1, plus listed versions 1.14.11-1 |
1.14.11-1+deb9u1 |
simplesamlphp/simplesamlphpPackagist |
before 1.14.17, plus listed versions v1.12.0v1.13.0v1.13.0-rc1v1.13.0-rc2v1.13.1 Show 19 moreShow lessv1.13.2v1.14.0v1.14.0-rc1v1.14.1v1.14.10v1.14.11v1.14.12v1.14.13v1.14.14v1.14.15v1.14.16v1.14.2v1.14.3v1.14.4v1.14.5v1.14.6v1.14.7v1.14.8v1.14.9 |
1.14.17 |
simplesamlphpUbuntu:Pro:16.04:LTS |
All versions, plus listed versions 1.13.2-11.14.0-11.14.0-1ubuntu21.14.0-1ubuntu2+esm1 |
None known |
History
| When | Changed | Sources |
|---|---|---|
| 2026-11-03 | aliases | EUVD |
| 2026-11-02 | created | CVE List, GitHub Advisories, NVD, OSV |
References
lists.debian.org/debian-lts-announce/2018/02/msg00008.html
debian.org/security/2018/dsa-4127
simplesamlphp.org/security/201710-01
nvd.nist.gov/vuln/detail/CVE-2017-18122
github.com/simplesamlphp/simplesamlphp/commit/e2d53086abbb253efb24ddcb49b116246eb0b6ca
github.com/FriendsOfPHP/security-advisories/blob/master/simplesamlphp/simplesamlphp/CVE-2017-18122.yaml